Time interval measuring device



Jan. 2, 1951 G. A. LOCKE TIME INTERVAL MEASURING DEVICE 5 Sheets-Sheet 1 Filed April 16, 1945 ATTORNEY lNl/EN TOR A. LOCKE FIG. 3

Jan. 2, 1951 G. A. LOCKE 2,536,193

TIME INTERVAL MEASURING DEVICE Filed April 16, 1945 5 Sheets-Sheet 3 POLA 9/250 INVENTOR A LOG/(E A TTORNEV Jan. 2, 1951 G. A. LOCKE 2,536,193

TIME INTERVAL MEASURING DEVICE Jan. 2, 1951 e. A. LOCKE TIME INTERVAL MEASURING DEVICE 5 Sheets-Sheet 5 Filed April 16, 1945 om 27 3mm 2m 3m n owm 2w. 0 3 0 2 on 8 3 em 0 m2 m9 5. m2 3 mm 3 3 am. :2 mm. 3. 8. mm S 3% mm v Edd n3 931.33 E Qmmohwmm 8m x32 Qufiwmwmo Sh xwdm 1P8 Ha Patented Jan. 2, 1951 TIME INTERVAL MEASURING nEvicE George A. Locke, Glenwood Landing, N. Y., as-

signor to Bell Telephone Laboratories,- Incorporated, New York, N. Y., a corporation of New York.

Application April 16, 1945, Serial No. 588,526

19 Claims.

This invention relates to time interval measuring devices and particularly to a system for the measurement of intervals between key-lever manipulations in keyboard operating technique.

More specifically, the invention relates to the measurement of the interval between ending of transmission of one and the beginning of transmission of the next of any two successive t'ele graph code combinations transmitted under the control of a keyboard transmitter.

An object of the invention is to measure the intervals between successively transmitted code combinations.

Another object of the invention is to measure the interval as an accumulation of discrete increments of time.

Another object of the invention is to accu mulate increments of fixed and equal duration until a predetermined number of increments has been accumulated and thereafter to accumulate increments of progressively greater duration.

Another object of the invention is to record characters representative of the duration of each interval timed.

Another object of the invention is to provide a predetermined upper limit of intervals to be measured and to represent all intervals exceeding the limit by a single character.

In accordance with the preferred embodiment of the invention, signals generated by a keyboard transmitter are received by a receiving relay and are repeated by the relay to a teletypewriter printer which records characters corresponding to the received signals. A relay for controlling the timing mechanism is also responsive to the signal. The latter relay, upon responding to the start impulse of a received code combination, dis ables a normally operative start-stop oscillator and also recycles a character timing. circuit which holds the oscillator disabled for the interval of one code combination, When the stop impulse of the code combination is received the character has timed out and the oscillator is restarted.

The oscillator is coupled'to a detector which derives impulses at the rate of one per cycle of the oscillator. The impulses are applied to a counting chain of electron discharge tubes, the tubes being activated in succession at equal intervals, these intervals'being the fixed and equal in crements of time hereinb'efore mentioned. As each tube is activated it operates a relay which transfers an energizing path from a coding relay associated with the transfer relay to the armatureof the transfer relay controlled by the next tubein the counting. chain.

The last tube in the counting chain operates two relays one of which is a transfer relay and the other of which activates a condenser charging circuit. The grids of a plurality of grid-controlled tubes representing a secondary counting chain are connected to the condenser charging circuit so that the grids become increasingly and equally positive in unison with the charging of the c0n-' denser. The cathodes of the tubes in the secondary counting chain are progressively more positive" from beginning to end of the chain, and are initially sufficiently positive that none of the tubes in the secondary counting chain is conductive. As the condenser charges the grids render the tubes conductive in succession and each tube operates a transfer relay which transfers the previously mentioned energizing path from a coding relay associated with each transfer relay to the armature of the transfer relay associated with the next tube in the chain. The transfer relay associated with: the last tube in the secondary counting chain is operable to transfer the energizing. path from the coding relay primarily associatedwith it to a final coding relay.

Each of the coding relays is operable to activate a set of storage relays which in turn set up a permutation code combination on the contacts of a local telegraph transmitter. Preferably these codes are assigned in a convenient order, such as'an alphabetical order beginning with the letter A for the coding relay controlled by the transfer relay associated with the first counting tube in the first counting chain. The local transmitter isconnected to a teletypewriter printer for record'- ing the characters corresponding to the codes set up on the transmitter contacts under the control of the coding relays.

Upon reception of the start impulse of a code combination generated by the keyboard transmitter, the oscillator is again stopped, the energizing path through the armatures and front-contacts of all operated transfer relays and through the armature and back contact of the first unopera-ted transfer relay to its associated coding relay is completed so that the coding relay is operated to set up its code through the storage relays on the transmitter contacts; and the transmitter is-set inoperation for one code cycle. The character corresponding to the code is thereupon recorded by the teletypewriter printer associated with the local transmitter. Following the storing of the character in the storage relays and the starting. of the local transmitter, the counting tubesare extinguished, the operated transfer relays and the operated coding relay are released and the system awaits the next counting opera-' mit another signal combination, and the begin ning of the next signal combination transmitted. If the letter A is printed, this indicates that the interval elapsing between the two signal combinations is not greater than one increment of time recognizable by the primary counting chain. If the letter B is printed, this indicates that the interval exceeds one increment but does not exceed two increments of time. extends beyond the number of increments of time which the first counting chain is adapted to.

count, the character printed will represent an interval comprising the total of the fixed and equal increments recognized by the first counting chain plus one or more of the unequal increments of time recognized by the second counting chain under the control of the condenser charging circuit. The printing of the character represented by the last coding relay indicates that the inerval is of an indeterminate duration exceeding any interval which the system is adapted to measure.

The copy produced by the printer associated with the local transmitter may be compared with the copy produced by the printer which receives signals from the keyboard "transmitter for the purpose of allocating the characters representing the intervals between signals transmitted by the keyboard transmitter to the characters representing those signals. In this way it may be determined whether individual operators of key-'- board mechanisms exhibit unusual or characteristic delays in reaching and operating certain keylevers on the keyboard, and by means of special training and extensive practice, faults or undesirable habits in keyboard techniques of operators may be corrected. 1

For a complete understanding of the invention reference may be had to the following detailed description to be interpreted in the light of the accompanying drawings in which:

' Figs. 1, 2, 3 and 4, contained on separatesheets, when arranged as shown in Fig. 5, show a complete time interval measuring system in accordance with the present invention; and

Fig. 6 shows a set of representative timing diagrams.

' Referring now to the drawings and particularly to Fig. 1, the reference numeral H designates a keyboard controlled transmitter of start-stop permutation code telegraph signals which may be of the type shown in Patent 1,595,472 granted August 10, 1926 to H. L. Krum. The disclosure of the foregoing patent is incorporated herein by reference, to the same extent as if the disclosure "thereof had been embodied herein in run. Key- If the interval Y The armature of receiving relay M is connected to ground and the marking contact thereof is connected to one terminal of the selector magnet of a teletypewriter printer I1, the other terminal of which is connected to battery l8. Teletypewriter printer I! may be of the type shown in Patent 1,745,633 granted February 4, 1930 to S. Morton et al. or it may be of the type shown in Patent 1,904,164 granted April 18, 1933 to S. Morton et al. The disclosures of either or both of these patents are incorporated herein by reference to the same extent as if fully included herein. Signals transmitted from keyboard transmitter II will be received by receiving relay l4 and will be repeated to teletypewriter printer I! which will record the characters and perform the functions corresponding to the signals.

Receiving relay 16 which responds to the signals in the same manner as relay l4 has its armature connected to the positive terminal of grounded battery l9 and its marking contact connected through the operating winding of biased polar relay 2| to the main anode 22 of a cold cathode gas-filled electron discharge tube 23. The cathode 24 of tube 23 is connected through resistor 26 to the negative terminal of grounded battery 21. The control anode 28 of tube 23 is connected through resistor 29 and condenser 3| to the cathode of the tube and is also connected through resistor 29 to the anode of a diode electron discharge tube 32 which is preferably a vacuum tube.

A potential difference for operating tube 32 is derived from batteries 33 and 34 interconnected by a potential divider comprising resistors 36, 31 and 38. The cathode of tube 32 is connected to the junction of resistors 3'! and 38 and the anode of the tube is connected through variable resistor 39 and fixed resistor ll to the junction of resistors 36 and 31. Assuming that relay 16 is in the marking condition and has been in this condition for some time and that gas-filled tube 23 is conductive the current flowing in the main gap of tube 22 maintains the lower terminal of condenser 31 at a substantially positive potential due to the low voltage drop in this type of tube. At this time the upper terminal of condenser 3! is maintained at a slightly less positive potential, the difierence being the voltage drop across resistor 29. Thus condenser 3| has only a very small charge. Upon the reception by relay is of the start impulse of a permutation code signal combination, the armature of that relay will move to the spacing contact, interrupting the anode circuit of tube 23 and quenching that tube. Upon the quenching of tube 23 the cathode 2d of the tube and the lower terminal of condenser 3| swing toward negative potential and by virtue of the fact that condenser 35 has only a small charge between its plates the upper terminal is likewise carried negative. With the upper terminal of condenser 3| carried negative the anode of tube 32 is carried negative and this tube ceases to be conductive. Condenser 3! now begins-t0 charge through resistors 36, 4| and 39 and the values of the resistors and of condenser 3| are such that the development of a potential across condenser 3| and therefore between the cathode 24' and control anode 23 of tube 23 sufficient to produce a discharge between these electrodes of the tube will not occur until one permutation code character interval after the quenching of tube 23 which is approximately .163 second at a printing telegraph operating frequency of sixty words per minute. If the armature of relay l6 is on the marking contact in response to the stop impulse, as it should be, at the time of the occurrence of a discharge between the cathode 24 and control anode 28 of tube 23, the discharge will transfer to the main gap of the tube. Upon the refiring of tube 23 the cathode 2d of the tube and the lower terminal of condenser 35 return to their initial substantially positive potential and due to the fact that condenser 3i is now charged positivel on its upper terminal this terminal is carried positive, thus making the anode of tube 32 highly positive and causing the tube to become conductive. Tube 32 provides a low resistance path for the discharge of condenser 3! to its steady state condition of a very small charge which is positive on the lower terminal and negative on the upper terminal.

It will be apparent that tubes 23 and 32 com prise a character timing circuit for pre enting the flow of current through the operating wind- 'ingof relay 2!, which is included in the anode circuit of tube during the reception by relay contained in the code combination being received from transmitter H, and for causing this winding to be reenergized at the end of a permutation code character interval when the stop impulse is received. Variable resistor 39 per-- Inits the timing of the character timing circuit to be adjusted so that the refiring of tube may be accurately adjusted to the signaling frequency of transmitter H.

Upon the quenching of tube 2 3 in the manner hereinbefore described current'in the operating winding of relay 2 I is interrupted and the armature. of the relay is operated by the biasing winding to the spacing contact. The negative terminal of grounded battery 49 is connected to the armature of relay 2! and the spacing contact is connected through resistor 43' and seriall connected inductively coupled coils t3 and 59. to ground. Under these circumstances a steady direct. current will flow in the coils =38 and 49.

Coils i9 and 19 together with condenser 5i connected in parallel therewith form an oscillatory circuit. The junction of resistor ii and coil 98 is connected through resistor 52 to the grid of the left-hand triode section of electron discharge tube 53 and the junction of coils it and Q9 is connected through variable resistor 55 to the cathode of the left-hand triode section of the tube. The anode. of the left-hand triode section of the tube connected through resistor 58 to the positive terminal of grounded battery 5'1.

With relay 2I operated to spacing and steady direct current flowing in coils it and 2 9 the grid of the left-hand triode section of tube 53 is negative with respect to the cathode by the potential difference across coil t9 and the tube is held non-conducting. Condenser 5| has a small voltage impressed across it due to the steady ohmic potential difference across coils 5'9 and 49 in series. This condition is maintained while the character is being timed by tube 23. Upon the refiring of tube 23 and reoperation of relay 2| to marking. the energy stored in the magnetic field of coils i8 and 49 causes. the circuit to begin to oscillate. The inductive value of coils i8 and 49 andv the capacitative value of condenser E! are preferably such that the circuit oscillates at approximately 159 cycles per second so that the duration of each cycle is approximately .007 second. A portion of the oscillatory voltage developed across coil 48 is applied between the grid and the cathode of the left-hand triode section of tube 53. This tube is being operated on the linear portion of its characteristic so that an oscillatory current results and this oscillatory current flows in the coil 99 which is connected in the return circuit between the cathode of the left-hand triode section of tube 59 and the anode battery 57. This induces an oscillatory current in the coil 48 through their mutual inductance, and thus the left-hand triode section of tube 53 serves to supply energy to replace that lost by resistive dissipation in the resonant circuit. The variable resistor 54 is adjusted so that oscillation continues at the amplitude at which it started.

The Voltage developed across the resonant circuit is applied through resistor 59 to the grid of the right-hand triode section of tube 53 which has its cathode connected to ground. The anode of the right-hand triode section is connected through resistors 59 and 55 to battery 51 and the right-hand triode section of tube 53 serves as a detector. When the grid of the right-hand triode section of tube 53 is negative with respect to the cathode no current flows and when the grid is positive with respect to the cathode current flows through resistor 59 thus causing the potential of the anode of the right-hand triode section of the tube to rise and fall.

The anode of the right-hand triode section of the tube 53 is connected to conductor ti which extends into Fig. 2 and. is there connected to one terminal of each of the condensers 62, 63, 64, 66, 61, 68, 69 and II. The other terminals of these condensers are connected to the control anodes I2, l3, 14, I6, TI, I9, I9 and SI, respectively of tubes 82, 83', 84, 86, 81, 83, 89 and 95, respectively, which may be similar to tube 23 in Fig. 1. Each time the anode of the detector section of tube 53 swings toward positive, a positive pulse is impressed through the condensers on the control anodes of the tubes with which they are associated.

The cathodes 92, 93,. 94,96, 91, 98, 99 and IOI of tubes 82, 83, 84, 86, 81, 88, 89 and 9|, respectively, are connected through cathode resistors I02, I03, I04, I06, I01, I08, I09 and III, respectively, to the negative terminal of grounded battery H0. The negative terminal of battery H0 is also connected through resistors and I09 to the positive terminal of grounded battery I05. The junction of resistors 95 and I96 is connected by resistor II2 to the control anode 72 of tube 82. When tube 82 is not conductive, so that there is no potential difference across cathode resistor I02 the potential supplied to the control anode I2 of the tube from the junction of resistors 95 and I09 is insufiicient to fire the tube. However, when a positive pulse is impressed through condenser 62 to the control anode 12 of tube 82 from conductor til the control anode is made. sufliciently positive with respect to the cathode 92 to fire the tube. When tube 82 becomes conductive the potential diiierence across its cathode resistor Hi2 applies a priming potential through resistor II3 to the control anode 1-3 of tube 83 so that when the next positive pulse is impressed on condensers 62, 63, 64, 68, 61, S8, 69: and TI tube 83 will be fired. In similar relation to the priming resistor I I3, priming resistors H4, H6, H1, H8, H9 and HI are connected between the cathodes and control anodes of Sueceeding tubes in the chain. From this it will be apparent that with none of the tubes in Fig, 2 conductive tube 82 will be fired in response to the first positive pulse impressed on the condenser, tube 83 will be fired in response to the second pulse, tube 84 will be fired in response to the third pulse and so on until all of the tubes have been fired so that the tubes will count the cycles of oscillation generated by the resonant circuit in Fig. 1. A chain of eight counting tubes has been shown in Fig. 2 but it will be understood that the chain may be extended or diminished as desired.

The main anode I22 of tube 82 is connected through the operating winding of a transfer relay I32 to conductor I38. Similarly, the main anodes I23, I24, I26, I21, I28 and I29 of tubes 83, 84, 86, 81, 88 and 88, respectively, are connected through the operating windings of transfer relays I33, I34, I36, I31, I38 and I39 to conductor I38. The main anode I3I of tube III is connected through the operating winding of transfer relay MI and then serially through the operating winding of relay I48 to conductor I88. The left-hand or normal or back contact of transfer relay I82 is connected through the locking winding of that relay and through the winding of a coding relay I42 to conductor I45. Similarly, the corresponding contacts of relays I83, I34, I38, I31, I3 I39 and MI are connected through their locking windings and through the windings of coding relays I43, I44, I45, I41, I48, I49 and I5I, respectively, to conductor I45. Conductor I45 terminates at the negative terminal of grounded battery I58. The armature of relay I82 is connected to conductor I56 which extends into Fig. 1 and is connected to the right-hand contact of a relay I58. One terminal of the operating winding of relay I58 is connected to the marking contact of relay 2I and the other terminal is connected to ground. With relay 2i in the marking condition, which is the condition when the oscillatory circuit is in operation, the operating winding of relay I58 is energized and holds the grounded armature on the left-hand contact so that ground is not connected to conductor I56. Thus in the condition of the system shown in Figs. 1 and 2 there isno energizing circuit for the locking winding of relay I32 and the winding of relay I42.

The right-hand or off-normal or front contact of relay I32 is connected to the armature of relay I 33. Thus when tube 82 operates relay' I32 the conductive path including conductor I59 is disconnected from the locking winding of relay I32 and the winding of relay I42 and is extended to the locking winding of relay I83 and the winding of relay I43. Similarly the right-hand contacts of relays I38, I34, I35, I81, I38 and 589 are connected to the armatures of relays I34, I31, I33, I38 and MI, respectively, so that as each of these relays is operated in turn it disables its own look.- ing winding and associated coding relay and prepares an energizing circuit for the locking Winding of the following transfer relay and associated coding relay. The right-hand contact of transfer relay I4! is connected to conductor I59 which extends into Fig. 3. j

The left-hand or normal contact of relay I48 is connected to ground and the right-hand or offnormal contact is connected through variable resistor I8I to the positive terminal of grounded battery I82. The armature of relay I48 is connected through conductor I83 to one terminal of condenser I 64, the other terminal of which is connected to ground. Conductor I63 extends into Fig. 3 and is connected through current limiting resistors I'II, I12, I13, I14, I15, I16, I11,

, I18 and I19 to the grids of electron discharge tubes IBI, I82, I83, I84, I85, I86, I81, I88 and I89, respectively. These tubes are preferably vacuum triode tubes.

A potential divider comprising resistors 28I, 2H and 22I is connected between the positive terminal of grounded battery 288 and ground. The anode of tube I8I is connected through the operating winding of transfer relay I9I to the junction of resistors 28I and 2| I and the cathode is connected to the junction of resistors 2H and 22!. Resistor 22I provides a positive potential of the cathode of tube I8I relative to ground of about 12 volts. Resistor 2II provides a positive potential of the anode of tube I8I relative to the cathode of about 100 volts. Thus with the armature of relay I48 on its normal contact and condenser I84 discharged, the grid of tube I8I has a negative bias of about 12 volts and the tube is cut off.

Tube I82 has its anode and cathode similarly associated with the operating winding of the transfer relay I92 and with a potential divider comprising resistors 282, 2I2 and 222. Similarly tube I83 is associated with the transfer relay I93 and with a potential divider comprising resistors 2E3 and 223, tube I84 is associated with a transfer relay I94 and with a potential divider comprising resistors 284, 2I4 and 224, tube I85 is associated with a transfer relay I and with a potential divider comprising resistors 285, 2I5 and 225, tube I86 is associated with a transfer relay I98 and with a potential divider comprising resistors 296, 2I8 and 225, tube I81 is associated with a transfer relay I91 and with a potential divider comprising resistors 281, 2I1 and 22?, tube I88 is associated with a transfer relay I98 and with a potential divider comprising resistors 288, 2I8 and 228, and tube I89 is associated with a transfer relay I99 and with a potential divider comprising resistors 289, 2I9 and 229.

The total resistance of each of the potential dividers is the same and resistors 2I I, 2I2, 2I3, 2E4, 2I5, 2H, 2I1, 2I8 and 2I9 have the same value so that the tubes in Fig. 3 have equal voltage between their anodes and cathodes. Resistors 222, 223, 224, 225, 226, 221, 228 and 229 are progressively of higher value than resistor 22I and accordingly resistors 282, 283, 284, 285, 286, 281, 288 and 289 are correspondingly progressively smaller than resistor 29L Thus the tubes I82, I83, I84, I85, I88, I81, I88 and I89 have progressively greater negative grid bias. Upon the operation of relay I48 to its right-hand or offnormal contact under the control of tube 9| in Fig. 2, condenser I64 begins to charge. The charging rate is adjustable by means of variable resistor I5I and as the condenser charges, the

grids of the tubes in Fig. 3 swing positive with respect to ground. The constants of the condenser charging circuit are preferably such that tube I8I will be rendered sufiiciently conductive to operate transfer relay I9! about .010 second after the armature of relay I48 reaches the righthand contact. Thereafter, the remaining tubes in Fig. 3 are rendered conductive in succession as condenser I64 continues to charge and they become conductive at intervals dependent upon their individual grid bias values and the characteristics of the condenser charging circuit. In accordance with one embodiment of the invention, the constants of the condenser charging circuit and the grid bias values have been so chosen that the final tube I89 will be operated about .320 second after the interval measuring opera assessetion was started by ac i ation of the oscil r in Fig. 1 and this intcrvalis substantially equal to. the time of two permutation code signal combinations including start and stop impulses at a sig,

naling speed of sixty words per minute.

Gonductor 15-9 which enters Fig. 3 from Fi 2 is connected to the armature of transier relay [-91 and the left-hand or back or normal contact of the relay is connected through the locking winding of the relay and the winding of a coding relay 23! to the negative terminal of grounded battery 2 39. The right-hand or front or off-norma'l contact of relay i9! is connected to the .armature of the .next transfer relay v19 2. The 'lefthand or back or normal contacts of relays I92, I93, I94, l95, I96, I97, I98 and 1 99 areconnected through locking windings of those relays and through the windings of coding relays 232, 233, 234, 235, 236, 237, 238 and 239 to battery 230. The right-hand or front or off-normal contact of each of these trans-for relays with the exception of relay '99 is connected to the armature of the counting relay following it. The righthand contact of relay l-QH which is the last of the transfer relays is connected through the winding of coding relay 2-40 to battery 236. As each of the transfer relays in Fig. 3 is operated, it transfers the conductive path of conductor I59 from the winding of the coding relay associated with it to the winding of the coding relay associated with the next transfer relay. Finally the transfer relay 1 99 upon being operated, transfers the conductive path to the final coding relay 2%. Each of the coding relays in Figs, 2 and 3 is provided with five grounded armatures and five iront contacts, The live front contacts of each coding relay are connected in permutational combination to live of ten conductors, five of which are designated by the reference numeral 25] and the other five of which are designated by t e reference numeral 252. The conductors 251 represent marking conditions and the com duotors 12,52 represent spacing conditions. Conductors 25l extend into Fig. 4 and are connected through the marking operating windings of five polar locking relays 25,3, 254, 255, 251 and 258 and through the marking operating windings of live .polar code storage relays 2,61, 2.62, 263, 264 and 265 to the negative terminal of grounded batte y Conduc o s 252 also ext nd i to Fig. {i and are connected through the oppositely poled spacing operating windings of locking relays :25'4, 256, 2.51 and 258 and through the spacin operating windings of code storage relays 2B], 252, 2.63., 264 and 2mm battery sci.

The armatures of the locking and code storage relays in Fig. 4 are connected to ground. The armatures of code storage relays 261, 262,263, 254 and 265 are mechanically biased toward their spacing contacts by individual springs. When any one of the coding relays in Figs. 2 and 3 is operated Over the conductive path including conductor I30 or conductors its and we, ground will be connected in permutational combination to the Inarking or spacing operating winding of each of the locking relays and each of the code storage relays in Fig. 4. Ifhose relays which have the circuit of their marking operating windings completed will operate their armatures to the marking contacts, which in the case of the lock ng relays are connected to the five conductors 25! and in the case of the code storage relays are dead contacts. Each locking relay so operated establishes a locking circuit for itself -and its associated code storage relay from ground through its armature and marking contactiits own marking operating winding and that of its associated code storage relay to battery 28], Any pair of relays in Fig. 4 comprising a code storage relay and associated locking relay which is already operated to the marking condition from ground on the armature of the locking relay through the marking contact, the marking operating windings of the locking relay and associated code storage relay to battery 25! will remain in that condition. Any of the pairs of relays which were previously in the marking condition and which have the circuits of their spacing operating windings completed by the coding relay will be operated to spacing and their locking circuits will be interrupted. The biasing springs associated with the armatures of the code storage relays 26L 262, 263, 264 and 265 hold the armatures in engagement with their spacing contacts, so that no locking of the code storage relays in the spacing condition is HGLCBS sary, and their armatures will leave the spacing contacts only upon energization of their marking operating windings. The locking and code storage relays have no normal condition, but having been conditioned in accordance with the code represented by one of the coding relays of Figs. 2 and 3, they will remain in that condition until another coding relay operates and changes their combinational condition.

The spacing contacts of the five code storage relays are connected to normally open contacts 26.1, 263, 269, 215 and 212 of a machine trans mitter comprising transmitting cams 213, :2", 276, 21'! and 218 securedto a shaft 219 driven from motor 28! through gears 232 and normally disengaged jaw clutch 233. The transmitting contacts when closed extend a conductive path through the operating winding of ,a biased polar relay 28 1 to battery 285. The armature of relay 284 is grounded and the marking contact is connected through the selector magnet of a teletype writer printer 28? to battery 2.38. Teletypewriter printer 28? may be of the same type as teletypewriter printer 9'! in Fig. 1. Shaft 21:9 also has secured thereto a start ca 289 for closing a pair of normally open contacts 291 representing the start impulse of telegraph signals. The machine transmitter operates on an inverse basis, by which is meant that a conductive path is completed from ground through the armature and spacing contacts of any one of the code storage relays and through the associated transmitting contacts when closed, and the operating winding of relay 284 to battery 286 to energize the operating winding of relay 284;an'd operate the armature to spacing-to represent a spacing signal. When the operating winding of relay 284 is not energized, the armature of that relay is held on the marking contact by current through the biasing winding. This mode of operation is thus distinguished from another well-known mode of operation in which a transmitter passes current to the operating winding of a receiving relay for the marking condition, and interrupts the current for a spacing condition, the armature of the receiving relay being operated to its spacing contact by current in the biasing winding.

'-Throughout the foregoing description it has been assumed that relay 2| in Fig. 1 has been steadily operated to its marking condition in response to a rest impulse between code combinations transmitted from keyboard transmitte'r H, that the oscillator had been in operation 11 and that the counting mechanism of Fig. 2 or Figs. 2 and 3 had been performing their counting and time measuring operation. If the interval has been long enough for the counting system to run through to the end of its operation, the conductive path of conductor I59 will be extended through the winding of the last coding relay 240 to battery 230. If the end of the counting system has not been reached when relay 2| is operated to spacing in response to the start impulse of the next signal combination received from transmitter II, the path will be extended through the winding of one of the coding relays preceding the relay 240 to battery 230. Upon the movement of the armature of relay 2| of Fig. 1 away from its marking contact, it interrupts the energizing circuit of the upper winding of relay I58. This relay is a spring biased polar relay and the armature will be operated by the biasing spring to its righthand contact. As the armature of relay 2! reaches its spacing contact, it reestablishes the flow of current through the inductance coils 48 and 49, thus stopping the oscillator and preventing further counting operation of the counting chain in Fig. 2 if that chain has not already counted through to the last counting tube 189.

Relay I58 upon being operated to its righthand contact completes a circuit from ground through the armature and right-hand contact of the relay, conductors I51 and I58 through the armatures and right-hand contacts of as many of the transfer relays in Fig. 2 as are operated and if all are operated through conductor I50 extending into Fig. 3 and the armatures and righthand contacts of as many of the transfer relays as are operated in. Fig. 3 and through the lefthand contact and locking winding of the first unoperated transfer relay and the winding of the coding relay associated therewith to battery I50 or battery 230. In case all of the transfer relays have been operated, then the circuit will not include the locking winding of any transfer relay but will be extended through the armature and right-hand contact of relay I 99 and through coding relay 240 to battery 230. The coding relay which is operated will attract its grounded armatures and complete the circuits of marking and spacing windings of the locking and code storage relays in Fig. 4 to condition those relays in accordance with the code combination assigned to the energized coding relay.

Relay I58 also completes a circuit from ground through its armature and right-hand contact, conductor I51, conductor 292 extending through Figs. 2 and 3 and into Fig. 4 and winding of clutch magnet 293 to battery 294. With clutch magnet 293 energized, clutch 283 is permitted to become engaged to drive shaft 219 and the cams carried thereby. Cam 289 first permits contacts 29I to close operating relay 284 to spacing for the start impulse of the signal and after the cam has reopened contacts 29I the cams, 213, 214, 216, 211 and 218 successively permit closure and effect reopening of their contacts 281, 288, 289, 21I and 212, respectively, for the transmission into relay 284 of the significant impulses of the code combinations.

About the time that cam 289 reopens the contacts 29I, a cam 296 carried by shaft 213 permits contacts 291 to close. These contacts complete a circuit from battery 298, closed contacts 291, conductor 299, extending from Fig. 4 through Figs. 3 and 2 into Fig. 1 and operating winding of a relay 30! to ground. The armature of rei2 lay 30I is connected to positive battery 302 and the left-hand contact which the armature nor-' mally engages is connected to conductor I30 which extends into Fig. 2 and as previously described has connected to it the main anodes of the tubes in Fig. 2 through the operating windings of their associated transfer relays, and in the case of tube 9 I, through the operating winding of relay I40 in addition to the transfer relay associated with the tube. Upon movement of the armature of relay 30! out of engagement with its left-hand contact, battery 302 is disconnected from this circuit thereby quenching all of the tubes in Fig. 2 and releasing as many of the transfer relays as have been operated and if all have been operated, releasing the relay Hi9. Relay I40 restores its armature to the left-hand contact, thereby reconnecting ground to conductor I63 to discharge condenser I64 and to restore the grids of the tubes in Fig. 3 to cut-off potential. With the tubes cut oif, any of the transfer relays in Fig. 3 that were operated are released.

The armature of relay 30! moves into engagement with its right-hand contact and completes the energizing circuit of the lower winding of relay I58. This winding has the same operative effect on the armature as the upper winding and accordingly restores the armature to the lefthand contact, thereby disconnecting ground from conductor I58. The effect of this is to open the energizing circuit through the operated one of the coding relays in Figs. 2 or 3 and through the locking winding of the associated transfer relay, thereby releasing the coding relay. The interruption of the circuit through the locking wind! ing of the associated transfer relay does not effect any change in the condition of that relay because the effect of the locking winding when energized is to hold the armature on the normal or left-, hand contacts so as to prevent interruption of the circuit of a coding relay which has been energized, should the operating winding of its associated transfer relay become energized after relay I58 has connected ground through conductor I51 to conductor I56.

With relay I58 operated to its left-hand con-v tact under the control of relay I, the energizing circuit of clutch magnet 293 including conductors I51 and I92 is also interrupted. With the clutch magnet released, clutch 283 will be disengaged at the end of one revolution and shaft 219 and the cams carried thereby will be stopped. Contacts 291 are opened by cam 29% shortly before the end of the revolution of shaft 219, at which time the stop impu se of the code combination received from keyboard transmitter .II is being or is about to be received, the armature of receiving relay I6 is engaging or is about to engage its marking contact, gas-filled tube 23 has been or is about to be refired to complete the en!- ergizing circuit for the operating winding of relay Zi to operate its armature to the marking contact, thus to complete the circuit of the upper winding of relay l58, which maintains its grounded armature on the left-hand contact after contact 291 opens and relay 30I operates its armature to its left-hand contact by the action of its biasing winding, interrupting the energizing circuitof the lower winding of relay I58 and reestablishing, over conductor I30, the anode circuit for the gas-filled tubes in Fig. 2 through the operating windings of the transfer relays in Fig. 2. With relay ZI operated to its marking contact, the flow of unidirectional current through 37: 9591 19.??? 2011 48 n s in r p l h r 13 onant circuit breaks into oscillation and begins operating the counting circuit for timing the interval preceding reception of the next code combination.

Consideration will now be given to a particular sequence of operations initiated upon response of relay IE to the start impulse of a received code combination. Relay 2 I is operated to spacing and interrupts the energizing curcuit of the upper winding of relay I58, permitting the Spring of this relay to operate the armature to the righthand contact. Over conductors I51 and I55 the locking winding of the first unoperated transfer relay in Figs. 2 or 3 and the winding of the associated coding relay are energized. Concurrently, over conductors I51 and 292, clutch magnet 293 is energized. Clutch 283 becomes engaged and shaft 219 begins to rotate. By the time that the end of the start impulse generated by contact 29I is approached, code storage relays 2M, 262, 263, 264 and 266 and associated locking relays 253, 254, 256, 251 and 253 will have been conditioned in accordance with the code combination represented by the operated coding relay in Fig. 2 or Fig. 3. Near the end of the start impulse generated by contacts 29 I, contacts 29'! close and complete the energizing circuit of relay 3M which restores relay I58 to its normal condition, which in turn interrupts the energizing circuit for the locking winding of the last unoperated transfer relay and the winding of the associated coding relay and also interrupts the energizing circuit for clutch magnet 293. This series of operations requires appreciable time and the outer dwell on cam 296 is of such length that as much time as possible sha11 be allowed for the energization of a coding relay and for the setting of the code storage relays before the energizing circuit for the coding relay is interrupted. With relay 2I operated to spacing, and the generation of oscillatory current by the resonant circuit interrupted, the activation of further gas-filled tubes in Fig. 2, if the counting chain has not already counted to the end, is prevented. However, if the counting chain in Fig. 2 is completely operated and condenser IE4 is charging and is operating the counting chain of Fig. 3, the stopping of the oscillator in Fig. 1 will have no effect on the charging circuit for condenser I64 and condenser I64 will not be discharged and the counting operation of the tubes in Fig. 3 will continue until relay 33! operates to its right-hand contact and disconnects battery 302 from conductor I39, thereby releasing relay I49. The interval between response of relay 2! to reception of the spacing impulse and the operation of relay 31H to its right-hand contacts may be suflcient for condenser I 64 to activate one, two or three of the counting tubes in Fig. 3, depending upon the allotted intervals between the tubes as determined by the constants of the condenser char ing circuit, and particularly if the counting chain in Fig. 3 has just begun to operate, at which point the intervals for operation of successive tubes are shorter than they are at the far end of the counting chain. Assume, for example, that at the time of operation of relay 2I to spacing and operation of relay I58 to its right-hand contact, transfer relay I9I in Fig. 3 is operated and transfer relay I92 is unoperated because tube I82 has not yet been activated. Ground connection will be extended over conductors I and I55, the armatures and right-hand contacts of all of the transfer relays in Fig. 2, conductor I59, the armature and right-hand contact of transfer relay 14 I91, the armature and left-hand contactand locking winding of unoperated transfer relay I92 and coding relay 232 to battery 230. This circuit will be maintained until contact 291 in Fig. 4 closes and operates relay SUI in Fig. 1, which in turn operates relay I53 to its left-hand contact. In the meantime the condenser charging circuit may have raised the grid of tube I82 and possibly tubes 83 and IE5 to sufiicient potential to render those tubes conductive. The upper or operating winding of relay I92 thus becomes energized and seeks to move the armature to the right-hand contacts, which would interrupt the energizing circuit of the locking winding of that relay and also interrupt the winding of relay 233. The locking winding of relay I 92 dominates that relay when energized and prevents the operating winding from operating the armature to the right-hand contact so that coding relay 232 remains energized and the conductive path of conductor I59 is not transferred to the armature of relay let. If tube !83 becomes conductive, the operating winding of relay I93 will be energized and the armature will be operated to the right-hand contact. If tube It! should become conductive before relay 3! operates and condenser its is discharged, relay I94 will also be operated. The operation of these relays will no change in the condition of the coding relays or the code storage relays because their armatures disconnected from the conductive path of conductor 559 at the right-hand contact of relay E92. Thus effective counting operation of the counting system in Fig. 3 is interrupted when relay 2! and in turn relay I58 respond to reception by relay it of the start impulse, although additional counting tubes in Fig. 3 may in fact be operated. Although continued operation of the counting chain of tubes in Fig. 2 cannot occur following operation of relay 2I to its spacing contact, assuming that the counting chain has not counted to the end, because of the fact that the oscillator is stopped and the counting chain requires additional pulses to continue counting, nevertheless the same type of locking circuits have been provided for the transfer relays in Fig. 2, as a safeguard against accidental activation of the first unoperated tube and consequent interference with the coding relays after one has been energized.

I The transmitter in Fig. 4 comprising cams 213, EN, 2H, 2.?8 and. 219 and the printer 231 preferably Operate at a higher speed of signal transmission than the keyboard transmitter i I and printer ii in Fig. 1. For example if printer I i is arranged to receive telegraph signals at a rate of about 62') Words per minute, as previously mentioned, the transmitter and printer in Fig. i may operate at a signal transmission speed of words per minute. The reason for this is that the previously described sequence of operations leading up to the energizaticn of clutch magnet 293 causes the initiation of the start pulse by contacts 223i to occur an appreciable interval after relay responds to the start pulse of a signal combination transmitted from keyboard transmitter i 5. With this relationship the transmitter in Fig. i may complete its transmitting operation and the printer 26'! may complete its receiving operation within the interval in which printer 2? is receiving the signal combination from keyboard transmitter II. Were it not for this relationship, and if the transmitter and printer in -Fig. should operate at the same speed, but with the lag due to the series of operations hereinbefore described, the operation of the transmitter and printer in Fig. 4 would extend over into the interval which the measuring system of Figs. 2 and 3 would begin to measure upon operation of relay 2| to marking responsive to the stop signal received by relay It. If the interval should be very short, due to almost immediate reception of a start impulse by relay I6, 0 that not even the tube 82 in Fig. 2 should have an opportunity to be fired and operate relay l 32, or if only the relay I32 of the transfer relays in Fig. 2 should become operated, the coding relays I42 or I 43 might become operated and change the condition of the code storage relays in Fig. 4 before the signal combination stored therein had been completely transmitted to printer 287. By operating the transmitter and the printer in Fig. 4 at the higher operating speed, the code combination representing the measured interval will have been completely transmitted by the transmitter in Fig. 4 to printer 281 by the time relay 2! again starts the oscillator in Fig. 1 under the joint control of relay I6 responding to the stop impulse of the received code combination and the timing tube 23.

' Printer 287 will record one character, representing th interval preceding each signal combination received from keyboard transmitter II. For the number of coding relays shown in Figs. 2' and 3 and assuming that they represent letter code combinations in alphabetical order, any one of the characters A to R will be printed. The first character printed by printer 281 following any interruption in transmission from keyboard transmitter II will be the letter R which represents the maximum interval that the measuring system is adapted to measure. Thereafter, providing no intervals longer than the interval represented by the letter R intervene, the characters printed will represent the actual intervals between code combinations received from keyboard transmitter II, it being remembered that intervals are measured in increments of time, these increments being fixed and equal in the case of the counting chain shown in Fig. 2 and fixed but not necessarily equal in the case of the counting chain in Fig. 3, and that the counting system takes no cognizance of fractions of such increments.

If a machine transmitter, such as a tape transmitter for example, should be substituted for keyboard transmitter H, printer 23! will invariably print the letter A, because the interval between code combinations transmitted by a keyboard transmitter is less than the interval in which tube 82 will be operated under the control of the oscillator.

It has been found convenient to employ tape printers as the printers I! and 28'! in Figs. 1 and 4, respectively. One advantage of this is that the tapes may be placed side by side and compared in order to determine whether there are recurrent letters in the tape produced by printer 281 relative to recurrent characters in the tape produced by printer ll. Another advantage in the use of tape printers particularly for the printer 281 is that it is not necessary to provide for the periodic transmission of carriage return and line feed signals to that printer from the transmitter in Fig. 4. In making a comparison between the copy produced by the two printers it must be born in mind that the printer 28! produces a character for every signal combination transmitted from the keyboard transmitter H whereas no corresponding character will appear in the copy pro- 16 ducedby printer II for non-printing function signals such as shift and unshift. This points to another advantage in using a tape printer as the printer ll, namely, that the number of non-printing functions may be minimized, since it is not necessary to transmit carriag return and line feed signals for the operation of a tape printer. However, it may be desirable to include all possible functions in a study of keyboard techniques, in which case the disparity between the number of characters in the two tapes introduced by all of the non-printing functions must be kept in mind.

Fig. 6 comprises a series of timing diagrams to illustrate graphically the sequence of operations beginning with reception of a signal combination by receiving relay is of Fig. 1. Diagram I represents a time scale in milliseconds for an interval of one signal combination. Diagram II represents a start-stop permutation code signal combination received by relay "5 at a signaling speed of 60 words per minute. Diagram II is related to Diagram I in such manner that time runs from the beginning of the start signal. The cycle of the transmitter from which the signal is transmitted begins and ends with the indicated rest points of Diagram II, from which it is seen that the transmitting distributor operates for a brief interval before the stop contacts are opened for the transmission of the start impulse. This interval is of the order of 6 milliseconds. The transmitter comes to rest about 163 milliseconds later or 157 milliseconds after the beginning of the start impulse.

Diagram III represents the timing of relay 2!. This relay is released upon response of receiving relay It to the start impulse, to disable the time measuring circuit and prevent a cumulative counting of further time increments. As previously described, this relay is prevented from reoperating to marking in response to marking impulses in the code combination or in response to the beginning of the stop impulse, by the character timing tube 23, which permits the relay to reoperate to marking about the time of the rest point in the stop signal. The shaded portion of this diagram represents approximately the operating time of the relay, by which is meant the time elapsing between the opening of the energizing circuit of the operating winding and the arrival of the armature at its spacing contact, in the case of the first shaded portion and the interval between the reestablishment of the energizing circuit for the operating winding and the disengagement of the armature from the spacing contact in the case of the second shaded portion.

Diagram IV represents the operating cycle of relay I53. This relay is released upon operation of relay 2| away from its marking contact and in turn completes the energizing circuit for the locking winding of the first unoperated transfer relay and for the coding relay associated therewith. The operation of the coding relay is represented in Diagram V, and due to the fact that it has five armatures to operate its operating time is appreciably slower than that of polar relays such as the relay 2! and relay I58, as indicated by the more extensive shaded portions of Diagram V. Relay I58 also causes the energization of clutch magnet 293, Fig. 4 and the starting of the local transmitter shown therein. The operation of the local transmitter is represented in Diagram VII. Clutch magnet 93 may also be relatively slow in operating because it is operable not only in optime, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting said predetermined number of impulses for activating said condenser charging circuit, a plurality of potential respon sive means controlled by said condenser for manifesting in steps the charging of said condenser, means controlled by said counting means and said potential responsive means for generating code signals individual to and representative of said impulses and said steps, and means controlled by said signal generating means for recording a character indicative of each signal generated.

6. In a device for measuring time intervals, an oscillator, means controlled by said oscillator for generating impulses at the rate of one impulse per cycle of said oscillator, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting said predetermined number of impulses for activating said condenser charging circuit, a plurality of potential responsive means controlled by said condenser for manifesting in steps the charging of said condenser, means controllable either by said counting means or said potential responsive means for generating code signals individual to and representative of said impulses and said steps, and means controlled by said signal generating means for recording a character indicative of each signal generated.

7. In a device for measuring time intervals, an oscillator, means for starting said oscillator at the beginning of an indeterminate interval to be measured, means for stopping said oscillator at the termination of said interval, means for generating impulses at the rate of one impulse per cycle of said oscillator, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting said predetermined number of impulses for activating said condenser charging circuit, a plurality of potential responsive means controlled by said condenser for manifesting in steps the charging of said condenser, means controllable either by said counting means or said potential responsive means for generating a signal individual to and representative of said impulses and said steps, and means controlled by said signal generating means for recording a character indicative of each signal generated.

8. In a device for measuring time intervals between cycles of an instrumentality operable in cycles initiated at random, an oscillator normally in operation when said instrumentality is at rest, means controlled by said oscillator for generating impulses at the rate of one impulse per cycle of said oscillator, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting said predetermined number of impulses for activating said condenser charging circuit, a plurality of potential responsive means controlled by said condenser for manifesting in steps the charging of said condenser, means controllable either by said counting means or said potential responsive means for generating code signals individual to and representative of said impulses and said steps, means responsive to initiation of a cycle of said instrumentality for stopping said oscillator and for activating said signal generating means, and means controlled by said signal generating means,

20 for recording a character indicative of the signal generated.

9. In a device for measuring time intervals between cycles of an instrumentality operable in cycles initiated at random, an oscillator normally in operation when said instrumentality is at rest,- means controlled by said oscillator for generating-- impulses at the rate of one impulse per cycle of said oscillator, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting said predetermined number of impulses for activating said condenser charging circuit, a plurality of potential responsive means controlled by said condenser for manifesting in steps the charging of said condenser, means controllable either by said counting means or said potential responsive means for generating code signals individual to and representative of said impulses and said steps, means responsive to initiation of a cycle of said instrumentality for stoppingsaid oscillator and for activating said signal generating means, means controlled by said signal generating means for recording a character indicative of the signai generated, and means for restarting said oscil' lator coincident with the end of the cycle ofsaid instrumentality.

10. In a device for measuring time intervals, means for generating impulses equally spaced in time, means for counting a predetermined number of said impulses, a condenser and a charging circuit therefor, means controlled by said counting means upon counting a predetermined number of impulses for activating said condenser charging circuit, a plurality of potential responsive means controlled by said condenser for manifesting in steps the charging of said condenser, means controllable either by said counting means or said potential responsive means for coding signals individual to and representative of said impulses and said steps, means for transmitting said coded signal, a recorder responsive to said transmitting means for recording a character indicative of the signal transmitted by said transmitting means, and means controlled by said transmitting means for restoring said counting means, said condenser charging circuit and said potential responsive means to unoperated condition.

11. In a device for measuring time intervals, means for generating impulses equally spaced in time, a counting chain of electron discharge tubes for counting a predetermined number of said impulses, a transfer relay associated with eachof said discharge tubes by having its operating winding connected in the anode circuit of the tube, a locking winding for each of said relays energizable through the armature and back contact of the relay for locking the relay in unoperated condition, a coding relay associated with each of said transfer relays by having its operating winding energizable in series with the looking winding of the transfer relay, means operable at the end of an interval to be measured for completing the circuit of the locking winding of the first unoperated transfer relay and the operating winding of the associated coding relay, means controlled by the operated coding relay for generating a signal combination individual to, and representative of the coding relay, and means controlled by said signal generating means for recording a character indicative of said code; combination.

lg, In a device for measuring time intervals,

and h'aving their cathodesprogressively 1 more positive than their grids wherebysaid other electr'on discharge tubes are rendered conductive in succ'ession 'as' said condenser charges, a transfer erelay associated-with each of said discharge tubes byhaving its operating winding connected in the anode circuit of the tube,a-lockingwinding for "each of said relays energizable through the arma -t'ure and' ba'ckcontact of the relay for locking the relay in unor'iera'ted condition, a coding relay I associated with each 'oi said transfer relays by;

" having its operating-winding energiZable-in' series -with -the locking winding of the transfer relay, means operable at the end of an interval to be measured for completing the circuit of the look-- ing windingot the first unoperated transfer relay 3- and the operating winding of the associated cod- 'ing relay,'-means'controlled by the operated coding relay for generating a signal cornbin'ation individuattoand representative of the coding relay, and means oontrolled by said signal generating means for recording acharacter'indicw 'tive'of said signal combination.

13. In adevice"for"measuring time intervals, means for generating "impulses equally spaced in time; a; counting chain of electron discharge tubes forcounting a'predetermined number of said iml 'pulses, a condenser and a charging circuit therefor me'ans controlled by said counting cha'in'upon counting said predetermined number of impulses for activating said condenser charging circuit, a series of other electron discharge tubes having their grids connected to said condenser and having their cathodes progressively more positive than their grids whereby said other electron discharge tubes are rendered conductive in succession as said condenser charges, a transfer relay associated with each of said discharge tubes by having its operating winding connected in the anode circuit of the tube, a locking winding for each of said relays energizable through the armature and back contact of the relay for locking the relay in unoperated condition, a coding relay associated with each of said transfer relays by having its operating winding energizable in series with the locking winding of the transfer relay, means operable at the end of an interval to be measured for completing the circuit of the locking winding of the first unoperated transfer relay and the operating winding of the associated coding relay, means controlled by the operated coding relay for generating a signal combination individual to and representative of the coding relay. means controlled by said signal generating means for recording a character indicative of said signal combination, and means also controlled by said signal generating means for restoring said counting chain to unoperated condition and for deactivating said condenser charging circuit and discharging said condenser.

14, In a device for measuring time intervals, means set in operation at the beginning of an interval to be measured for generating impulses equally spaced in time, a counting chain of cold cathode electron discharge tubes for counting a predetermined number of said impulses, a condenser and" a charging circuit Y therefor, means controlled by said counting chain upon counting 'said predetermined number of impulses foractivating said condenser charging circuit, aplurality 'of' grid-controlled vacuum electron discharge tubes having their grids connected to said condenserand having theirc'athodes progressively more positive with respect to their grids'whereby to' be rendered conductive insuccession by the charging of said condenser, a transferrelay associated with each of said cold cathode and vacuum electron discharge tubes-by having its operating winding connected in the anode circuit of-the tube, a locking winding for each of said relays energizable through the armatureand back contact of the relay for locking the relay in unoperated condition, a coding relay associated'with each of said transfer relays by having itsoperating winding energizable inseries with the locking winding of the transfer relay',-means operable at I the end of an interval to'be measured 'for' completing the circuit of the locking winding of the first unoperated transfer relay and the operating winding of the associated coding relayfmeans "controlled by the operated coding relay for generating a signal'combination'individual to and representative of the coding relay, means *c'ontrolled by said signal'generating means for regenerating means for quenching the-tubesof said ccunting chain'and for dea'ctivating 'saidcondenser charging circuit and discharging said condenser.

15. In a device for measuring time intervals,

means for generating impulses equally spaced in tirne; a counting chain of electron discharge tubes for counting a predetermined number-of said impulses, a transfer relay associated with each of said discharge tubes by having its operating winding connected in the anode circuit of the tube, a connection from the front contact of each of said relays to the armature of the relay associated with the next tube in said chain, a locking winding for each of said relays energizable through the armature and back contact of the same relay for locking the relay in unoperated condition, a coding relay associated with each of said transfer relays by having its operating winding energizable in series with the locking winding of ti e transfer relay, means operable at the end of an interval to be measured for connecting a source of potential to the armature of the transfer relay associated with the first tube of said chain whereby to extend said connection through the armatures and front contacts of all operated ones of said transfer relays and through the armature and back contact of the first unoperated transfer relay to the locking winding of said first unoperated transfer relay and associated coding means, means controlled by the operated coding relay for generating a signal combination individual to and representative of the coding relay, means controlled by said signal generating means for recording a character indicative of said code combination, and means also controlled by said signal generating means for disconnecting said source of potential from the armature of the transfer relay associated with the first tube in said counting chain and for restoring said chain to unoperated condition.

16. In a device for testing keyboard telegraph signal transmitter operating techniques, a key{- board transmitter, a receiving printer responsive to signals generated by said transmitter, a series 23 of counting instrumentalities for counting increments of time entering into the interval between the end of any signal combination and the beginning of the next signal combination received from said transmitter by said printer, means controllable by each of said counting instrumentalities for setting up a character code signal individual to said counting instrumentality, means for causing only the code signal setting-up means associated with the first unoperated counting instrumentality in any counting cycle to operate, and means controlled by the operated code signal setting-up means for recording a character corresponding to said code signal.

17. In a device for testing operation of a keyboard telegraph signal transmitter, a series of counting instrumentalities for counting increments of time entering into intervals between the end of one signal combination and the beginning of the next signal combination generated by a telegraph signal transmitter, means controllable by each of said counting instrumentalities for setting up a character code signal individual to said counting instrumentality, means for causing only the code setting-up means associated with the first unoperated counting means in any counting cycle to be operated, a telegraph transmitter controlled by the actuated one of said code setting-up means, and a teletypewriter printer adapted to receive the signals transmitted by the last-mentioned telegraph transmitter and to record the character represented thereby, whereby each recorded character is indicative of the duration of the interval between two signal combinations transmitted by said keyboard transmitter.

18. In a device for measuring time intervals, a. plurality of devices each adapted to count one of a number of equal increments of time entering into the interval to be measured, means controllable by said counting devices for generating code signals individual to the increments represented by said counting devices, means for activating said signal generating means only in response to the last increment of any interval, and means for recording a character indicative of each signal generated.

19. In a device for measuring time intervals, a plurality of devices each adapted to count one of a predetermined number of equal increments of time entering into the interval to be measured, a further plurality of devices each adapted to count one of a plurality of unequal and progrestively longer increments of time entering into the interval to be measured, means controllable by said counting devices for generating code signals individual to the increments represented by said counting devices, means for activating said signal generating means only in response to the last increment of any interval, and means for recording a character indicative of each signal generated.

- GEORGE A. LOCKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

